Illinois has explicit insurance guidance on transgender-related health care.

Regulations:

• Ill. Admin. Code tit. 50, § 2603.35 (Prohibited Gender Identity Discrimination)
  Summary:

  “A company that offers or provides group or individual health insurance coverage that is neither a grandfathered plan nor a plan offering excepted benefits shall not discriminate on the basis of an insured's or prospective insured's actual or perceived gender identity, or on the basis that the insured or prospective insured is a transgender person.”

• Ill. Admin. Code tit. 50, § 2007.60 (allows exclusions of GRS and cosmetic surgery)
  Summary:

  Exclusions:

  Excluding, “Sex change surgery, with respect to excepted benefit policies and grandfathered health plans, or surgical sterilization” and “ Cosmetic surgery, except that “cosmetic surgery” shall not include reconstructive surgery when the service is incidental to or follows surgery resulting from trauma, infection or other diseases of the involved part”

Bulletins and Announcements:

• Bulletin: Guidance Relating to Nondiscrimination in Healthcare Services in Illinois
  Issued by: Illinois Department of Human Rights (IDHR), the Illinois Department of Healthcare and Family Services (HFS) and Illinois Department of Insurance (IDOI)
  Issued on: June 26, 2020
  Summary:

  Clarifies protections under the Illinois Human Rights Act, in insurance, and Medicaid.

• Bulletin: Company Bulletin 2020-16 Health Insurance Coverage for Transgender, Nonbinary, and Gender Nonconforming Individuals, and for Individuals of All Sexual Orientations
  Issued by: Illinois Department of Insurance
  Issued on: June 15, 2020
  Summary:

  Reminding insurers subsequent to the announcement of the repeal of Section 1557 regulations that they are still subject to Illinois' prohibitions on transgender discrimination in insurance.

• Bulletin: Company Bulletin 2014-10, Healthcare for Transgender Individuals (2014)
  Issued by: Illinois Department of Insurance
  Issued on: July 28, 2014
  Summary:

  Prohibiting discriminatory exclusionary clauses that have “the effect of targeting transgender persons or persons with gender dysphoria such as: ‘Any treatment or procedure designed to alter an individual’s physical characteristics to those of the opposite sex.’ ‘Sex transformations and related services.’ ".